Back frame for pianos.



P. M. ZEIDLER.

BACK FRAME FOR PIANOS.

APPLICATION FILED JULY 18, 1912.

1,095,691. Patented May 5, 1914.

2 EHEETSSHEET 1.

P. M. ZEIDLER.

BACK FRAME FOR PIANOS.

APPLICATION FILED JULY18,1912.

M mm 4 7 s K n m a m s P 3 JW 5 s 9 9 Z 2 m s z TN? 0 v 6 o J 1 p Mawx PAUL M. ZEIDLER, OF MOUNT VERNON, NEW YORK.

BACK FRAME FOR- PIANOS.

Specification of Letters Patent.

Application filed Ju1y 18, 1912.

Patented May 5, 1914.

Serial No. 710,169.

To all whom it may concern Be it known that I, PAUL M. ZEIDLER, a citizen of the United States, and a resident of Mount Vernon, in the county of Westchester and State of New York, have invented certain new and useful Improve ments in Back Frames for Pianos, of which the following is a specification.

It is well known in the art that the back frame is practically the foundation and main stay of a piano structure, and furthermore that as heretofore made it has been subject to deterioration by reason of atmosphericand climatic conditions and changes, as Well as from the tension to which it is subjected by the strings of the instrument. In attempting to meet and counteract these difliculties the back frame has been made of many parts primarily united integrally into a heavy, cumbersome and expensive structure lacking in both resilience and durability.

The object of my invention is to meet and overcome the above named deficiencies, and to afford a relatively cheap but strong, light weight, rigid yet resilient structure of comparatively few parts rendered permanently one unit, and affording a high degree of resonance; and the invention consists in the specific construction and arrangement of parts described and claimed, whereby the component parts of the frame are made to interlock and reinforce each other; the distinctive and important feature being the dove-tailing of the wrest plank to the vertical styles of the back frame, whereby the whole wrest plank is anchored positively to the frame and cannot possibly yield or collapse under the strain exerted by the piano wires, all as hereinafter more fully set forth.

In the accompanying drawings, Figure 1, is an isometrical perspective of my improved piano back frame, looking toward the front side thereof; Fig. 2, is an inner side elevation of the upper end of the right hand end style or post; Fig. 3, is a similar view of the lower extremity thereof; Fig. t, represents a front elevation, broken away and partly in section, of the upper and lower portions of the frame; Fig. 5, represents a rear elevation, broken away, of the upper and lower portions of the frame; Fig. 6, is a top view of the frame; Fig. 7, a bottom view thereof; Fig. 8, a View of the rear side of the base of the wrest or pin plank; Fig. 9, is a transverse section taken upon plane of line 9-9, Fig. l. Fig. 10, is a detail of a portion of Fig. 6, showing a modification.

The wrest plank j), is composed of superposed layers of veneer in the usual manner, secured integrally to the base board p, said base board 2), and the back board 6, being positively coupled together by means of the styles '8, 8' 8', 8, instead of being simply glued to blocks interposed between them as heretofore. That is to say the only blocks used in the present construction are the narrow blocks a, a, which are glued to the inner sides of the base board 7), and the back board Z), at the upper edges thereof, simply for the purpose of closing the spaces between the styles 3, s s s and the opposed inner surfaces of said base board and back board 6, as will be understood more particularly by reference to Fig. 9, by which it will be seen that a clear space 0, is left between said boards and the upper ends of the styles,a space heretofore co1n pletely filled by blocks relied upon to bind the parts together, mainly by the aid of glue. Primarily the top blocks a, a, may first be secured to the inner sides of either the wrest base board 7), or the back board Z).

The positive interlocking of the base board p, back board Z), and styles 8, s 8 s, is attained by forming the upper ends of the latter with dove-tail tenons s, s,the inner sides of the wrest base board 79, and of the back board Z), being formed with corre sponding indentures or grooves for the reception of said dove-tail tongues s, s, as shown more particularly in Figs. 1 and 6 of the drawings. Shoulders s 8 formed on the styles at the inner or lower ends of the dove-tail tongues s, s, properly position the parts and sustain the base board p, and the back board Z), against movement downward upon styles. These shoulders 8 s, are of practical importance in helping to sustain the wrest plank 79, against the strain to which it is subjected by the piano strings, and hence are something more than a mere incidental feature of my improved structure of back frame.

The lower horizontal member (Z, of the frame is secured to the lower ends of the styles 8, s 8 8, either by dove-tailing as above, or by dowel pins d, d, the latter being shown in the specific structure of the drawings, as applied to the-lower ends of the outer styles 6', and .5'", while the lower ends of the intermediate styles 3 s, are formed with dove-tail tenons and fit in correspondingly shaped mortises in said lower member (Z, as shown particularly in Fig. 7.

The lining e, c, for the sounding board is made rigid with the end posts 8, s and lower member (Z, being in each case made in one piece therewith or rigidly attached thereto, as may be found most expedient,the preferable being the one piece structure.

m, m, are the usual sounding board. mutes doweled to the intermediate styles 8 s and abutting at either end against the lining c, c, as clearly shown in Fig. 1.

In this connection it is to be understood that any desired or requisite number of styles or posts may be used in the frame, and the latter otherwise modified to suit special conditions of use, so that I do not limit myself in this respect, the essential feature of the invention consisting in the method of forming the parts so that they interlock and reinforce each other.

In fact, although glue is preferably used on all the joints, it is not indispensable, as the structure is practically self-sustaining when put together, which may be readily accomplished without the aid of skilled labor. Furthermore the parts being machine-made to standard, may be transported in knock down or detached condition, to be assembled where most convenient,

By my construction I produce a light weight, inexpensive piano frame which combines rigidity and strength with the degree of resilience requisite to afford the resonance which is so essential in a piano of good quality and tone.

The construction of the upper portion of the frame particularly reinforces and sustains the wrest plank against the severe strain imparted thereto by the piano wires, and at the same time is of a light hollow conformation which materially aids resonance as compared with the heavy, solid, dead mass of blocking heretofore used between the styles and the wrest plank base and. back board.

As the frame is self-sustaining when put together, the parts need not be clamped for drying when glue is used, as will ordinarily be desirable.

The wrest plank, &c., being locked and held positively in position, cannot give way and disintegrate as where glue is relied upon mainly to hold the parts together, and hence the frame is especially adapted for use in damp climates and situations where moisture is prevalent, or where temperature or climatic conditions are variable.

By my method of construction I can pro duce a frame of a given size and capacity that will be at. least one third lighter in weight than heretofore, and much stronger and more durable and satisfactory in every respect. Furthermore the necessity for highly skilled labor is obviated, both in forming and assembling the parts; and the frame as unit is so light as to be easily and conveniently handled as such in the formation of the piano.

While the formation of the dovetail tenons on the styles or posts is obviously the most desirable method of carrying out my invention, it is also equally obvious that the same results could be attained by forming dovetail grooves in the styles or posts and the dovetail tenons on the adjacent parts, as indicated in Fig. 10.

hat I claim as my invention and desire to secure by Letters Patent is,

An upright piano frame comprising a series of styles and a wrest plank, the latter formed of a base portion and superposed layers thereon, the base portion and styles having respectively interlocking dove-tail mortises and tenons, a back-board, said backboard and styles having interlocking dovetail mortises and tenons, and the styles having shoulders against which the bottom edges of the back-board and base portion abut, and top blocks interposed between the styles and between the adjacent faces of the back-board and base portion and held thereto, there being a clear space between the back-board and base portion between the styles beneath the top blocks.

PAU L U. ZEIDLTJR. lVitnesses Geo. WM. lifrvr'r, Lnmm Mnrr'r.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

